The present invention relates to operating a communications network like a telecommunications network, for example. In particular, the present invention relates to operating a communications network, wherein a set of derived events occurs in dependence on at least one primary event in the communications network. Further, the present invention relates to a method, to a computer reliable storage medium, to a system, and to entities of the communications network enabling the operating the communications network.
A typical management network of a communications network comprises several levels for managing the communications network, for example a telecommunications network. In a management network of a communications network, every level has a certain management and/or communications network specific functionality being specific for this level and often depending on the (hierarchical) position of the layer in the management network. Each of these hierarchical levels, with the exception to the top level and the first-line level, has a double management function—manager function and agent function. Each level of the management network, with the exception of the first-line level, has a manager function with regard to the underlying level, and each level of the management network, with the exception of the top level, has an agent function with regard to the level before. Thus, a management of a communications network features a kind of hierarchical structure clearly defining the functions at every level of the management network of this communications network. See an example provided in FIG. 1 representing three levels of a (hierarchical) management structure in a telecommunications network and described below.
Each level of the management network comprises corresponding entities or elements being of physical and/or abstract nature. Thus, an entity of a hierarchical level can be a software and/or hardware (device) in a communications network. In the following, such entities or elements will be referred to as “network entities”. Depending on the level of the management network performing a functionality of a manager or an agent, or both, these network entities are managers, agents, or both. In the following, the terms manager or agent will be used in dependence on the functionality of the corresponding level of the management network and, thus, in dependence on the corresponding network entity of this level. For this reason, if a level of the management network represents both the manager and the agent level, a network entity comprised in this level will be a manager or an agent depending on the function to be performed in a given moment by this network entity.
Network management as such often refers to the Operation, Administration, and Maintenance (OAM) of communications networks like telecommunications networks at the top level. Network management is the execution of a variety of functions required for controlling, planning, allocating, deploying, coordinating, and/or monitoring the resources of a network, including performing functions such as initial network planning, frequency allocation, predetermined traffic routing to support load balancing, cryptographic key distribution authorization, configuration management, fault management, security management, performance management, bandwidth management, and/or accounting management. Further, in such a management system hardware and/or software are provided that support OAM functionality and provide these functions, for example, to network users and/or administrators. Thus, OAM includes facilities for operating, managing and maintaining networks.
Managers in a communications network are configured to start operations for the operation, administration and maintenance of the communications network. It is done by sending requests, which are performed by the agents, in particular, by the agents assigned to the corresponding managers. The managers receive then corresponding feedbacks, called responses, from the agents.
Network entities implementing the functionality of an agent in the communications network recognize events in the communications network relevant for the operation, administration and maintenance of the communications network (e.g. alarms), generate corresponding notifications, and transmit these notifications, usually as event reports, to the managers, in particular, to the managers the network entities are assigned to. Thus, an efficient network management is enabled.
An event mostly refers to changes in a system or communications network, which provoke a pre-defined reaction from a network entity. The occurrence of an event in a communications network is not predictable. Often it appears or occurs with a special set of circumstances in the communications network like performance bottlenecks, changes with regard to the configuration of the network, addition of new network entities, or faults in the communications network. An event is like a phenomenon located at a single point in space-time. Further an event can be a cause for one or more than one subsequent events in the communications network. In the following, events being not caused by other events in the communications network will be referred to as “primary events”, and events being caused by at least one previous event will be referred to as “derived events”.
The communication between the levels of a management network and thus between the managers and the agents is usually facilitated by management interfaces, called OAM interfaces. The implementation of these interfaces can be performed, for example, by appliance of protocols like Simple Network Management Protocol (SNMP), Transaction Language 1 (TL1), Extensible Markup Language (XML), or Common Object Request Broker Architecture (CORBA).
When considering FIG. 1, presenting a design of a conventional management network in a communications network like a telecommunications network, three levels of a hierarchical management structure are presented: the network element (NE) level 103, the element manager system (EMS) level 102, and the network manager system (NMS) level 101. According to the hierarchical structure of a conventional management network, the NE level 103 is managed by the EMS level 102, and the EMS level 102, in turn, is managed by the NMS level 101.
Each of the levels 101, 102, and 103 comprises corresponding network entities like network managers (NMs), element managers (EMs) being often manufacturer specific, and network elements (NEs). Each NE is managed by a certain EM, and each EM is managed by a certain NM. An NM, in turn, manages at least one EM, and an EM manages at least one NE in the communications network.
As already outlined above, the communication between the levels of a management network of a communications network and the corresponding network entities of the communications network is performed by specific interfaces between these levels. The connections between the levels 101, 102, 103 in FIG. 1 are outlined by lines between them. The communication between the NE level 103 and the EMS level 102 can be implemented by EM-NE-interfaces 105, the communications between the EMS level 102 and the NMS level 101, in turn, can be implemented by NM-EM-interfaces 104.
The recent developments of communications networks provide also direct NM-NE-interfaces 106 enabling direct communication between the NE level 103 and the NM. This is the case, for example, with regard to the standardizing activities of the 3rd Generation Partnership Project (3GPP), where an interface 107 standardized from the point of view of the NMS and called the “northbound interface” or Itf-N respectively has been introduced.
Thus, when managing a NE in a communications network, it is assumed that the management function can be performed either by an EM or by an NM.
A (tele-) communications network comprises a variety of network entities being capable of producing event reports or messages like alarm reports, for example. Further, in a (tele-) communications network exist several kinds of dependencies between the several network entities. For this reason, an event at one network entity in a (tele-) communications network may be a cause for further events in the same and/or in further network entities. As already outlined above, the event appearing at first will be referred to as “primary event” and the further events being caused by the primary event will be referred to as “derived event”.
These dependencies between events (based on dependencies between the network entities on the network configuration in general, for example) have to be visible to the corresponding managing layers or to the network management in general to allow a fast and efficient reaction to these events and to enable an efficient OAM of the communications network.
When turning to a more concrete example, a report of a primary event (e.g. alarm report) for a network entity (A) can be a cause for at least one further report of at least one further derived event (e.g. alarm reports, event reports concerning state changes, reports concerning changes of values of attributes, reports concerning relationship changes) for the network entity A and/or for further network entities (B, C, D, . . . ). To achieve an efficient management, control and/or monitoring of a communications network, the concerning reports have to be correlated in such a way in the relevant network entities, that the dependencies between the corresponding events are reflected in a well coordinated and clear way. Such correlations of event reports are mostly implemented by use of standardized parameters like “notification identifier” and “correlated notifications”, for example, wherein each report of a derived event comprises in its “correlated notification” parameter at least one (unique) “notification identifier” value of the corresponding at least one primary event. These dependencies between the events and/or event reports are provided by large data sequences comprising the corresponding parameter data.
The reports of derived events are important for the managing levels or for operators to derive a complete view of a state of a communications system. However, the transmission and use of such large data sequences providing overview of event dependencies and being an important help when managing a communications network on one hand, provide also disadvantages on the other hand because of their data volume. Thus, the use of such sequences being provided from the lower or agent levels to the upper or managing levels are cause for reduced performance of the involved network entities. Further, they are an additional cause for heavy data traffic and stress the functionalities of the involved interfaces. Additionally, as the correlation of event reports reflects the corresponding events being involved in the sequence of primary and derived events in the same and equal way, it is hard to differentiate at first the importance of the several events for a certain state of the communications network. Thus, the managing levels and/or operators can be distracted from the important events to less important or dispensable events.